Ultra-wide Band Antipodal Vivaldi Antenna Using Metasurface Lens for Gain and Front-To-Back Ratio (FBR) Improvement

This paper addresses the limited gain of conventional Antipodal Vivaldi Antenna (AVA) at higher frequencies. We propose a novel Metamaterial Lens Vivaldi Antenna (MLVA) design that overcomes this limitation by integrating an exponentially tapered antenna lens and a strategically placed Near Zero Refractive Index (NRZI) metamaterial lattice. The MLVA achieves exceptional wideband performance with a -3 dB gain bandwidth exceeding 148.6% from 3.7 to 25 GHz. The result demonstrates a peak realized gain of 11.8 dBi at 11.2 GHz, compared to 9.1 dBi conventional AVA, especially beyond 5 GHz. The compact MLVA design measures only 120 x 78 x 1.524 mm3 (1.48 x 0.96 x 0.0188 lambda 03) lambda 0 where free-space wavelength is the lowest frequency and is fabricated on RO4350 B substrate with a 50-ohm SMA connector. Key features of the design include exponential flaring, and trapezoidal lens geometries chosen for their inherent ability to effectively collimate and direct the spherical wavefront. The incorporation of a dielectric lens and metasurface further enhances gain and Front-to-Back Ratio (FBR) by directing the majority of energy in the end-fire direction. Experimental results validate the effectiveness of the proposed design, confirming simulation predictions. These outstanding characteristics make the MLVA a promising candidate for diverse wireless communication and radar applications demanding high data rates across a broad frequency range. This paper introduces a new type of antenna called the Metamaterial Lens Vivaldi Antenna (MLVA), designed to perform better at high frequencies than conventional Antipodal Vivaldi Antenna (AVA). By incorporating a special lens and innovative materials, the MLVA achieves a wide range of frequencies from 3.7 to 25 GHz and a high gain of 11.8 dBi at 11.2 GHz. The compact design (measuring 120 x 78 x 1.524 mm3 or 1.48 x 0.96 x 0.0188 lambda 03) has been validated through simulations and real-world tests. These improvements make the MLVA ideal for high-speed wireless communication and radar systems. The Metamaterial Lens Vivaldi Antennas (MLVA) offer higher gain and broader bandwidth than conventional Antipodal Vivaldi Antennas The design uses an exponentially tapered lens and NRZI metamaterial lattice to enhance high-frequency performance The compact MLVA, validated by simulations and experiments, is ideal for high-data-rate wireless communication and radar applications